(a) Field of the Invention
This invention relates to 2H-imidazo[4,5-b]pyridin-2-ones and -2-thiones, their preparation and their use as cardiotonics.
(b) Description of the Prior Art
Baldwin et al [J. Med. Chem. 20, 1189-1193 (1977)] prepared 2-(3-pyridinyl)-1H-imidazo[4,5-b]pyridine and 2-(4-pyridinyl)-1H-imidazo[4,5-b]pyridine by heating respectively, a mixture of 2,3-diaminopyridine and nicotinic acid or a mixture of 2,3-diaminopyridine and nicotinic acid or a mixture of 2,3-diaminopyridine and isonicotinic acid. Both of these compounds were found by Baldwin et al to be inactive when tested as inhibitors of xanthine oxidase.